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BMC Biol 2018 Jul 16;161:79. doi: 10.1186/s12915-018-0540-5.
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A gene regulatory network underlying the formation of pre-placodal ectoderm in Xenopus laevis.

BACKGROUND: The neural plate border ectoderm gives rise to key developmental structures during embryogenesis, including the neural crest and the preplacodal ectoderm. Many sensory organs and ganglia of vertebrates develop from cranial placodes, which themselves arise from preplacodal ectoderm, defined by expression of transcription factor Six1 and its coactivator Eya1. Here we elucidate the gene regulatory network underlying the specification of the preplacodal ectoderm in Xenopus, and the functional interactions among transcription factors that give rise to this structure. RESULTS: To elucidate the gene regulatory network upstream of preplacodal ectoderm formation, we use gain- and loss-of-function studies to explore the role of early ectodermal transcription factors for establishing the preplacodal ectoderm and adjacent ectodermal territories, and the role of Six1 and Eya1 in feedback regulation of these transcription factors. Our findings suggest that transcription factors with expression restricted to ventral (non-neural) ectoderm (AP2, Msx1, FoxI1, Vent2, Dlx3, GATA2) and those restricted to dorsal (neural) ectoderm (Pax3, Hairy2b, Zic1) are required for specification of both preplacodal ectoderm and neural crest in a context-dependent fashion and are cross-regulated by Eya1 and Six1. CONCLUSION: These findings allow us to elucidate a detailed gene regulatory network at the neural plate border upstream of preplacodal ectoderm formation based on functional interactions between ectodermal transcription factors. We propose a new model to explain the formation of immediately juxtaposed preplacodal ectoderm and neural crest territories at the neural plate border, uniting previous models.

PubMed ID: 30012125
PMC ID: PMC6048776
Article link: BMC Biol
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: dlx3 eya1 foxd3 foxi1 foxi4.2 gata2 hes4 msx1 myc npb pax3 six1 sox3 tfap2a ventx2 ventx2.2 zic1
GO keywords: neural crest formation [+]
Morpholinos: dlx3 MO1 eya1 MO1 eya1 MO2 foxi4.2 MO1 hes4 MO1 hes4 MO2 msx1 MO1 pax3 MO1 six1 MO1 six1 MO2 tfap2a MO1 ventx2.1 MO2 zic1 MO1

Article Images: [+] show captions
References [+] :
Ahrens, Tissues and signals involved in the induction of placodal Six1 expression in Xenopus laevis. 2005, Pubmed, Xenbase